The invention relates to an adaptor which can affixed to a rotatable disc record to be inscribed and/or read and having a specific outer diameter, in particular an optical disc. The adaptor has an annular body having an inner rim which bounds a center hole in which the disc record can be placed.
Such an adaptor is known from U.S. Pat. No. 2,285,139 (herewith incorporated by reference) of 1942 and intended to give gramophone records of different size the same dimensions to enable the records to be played on one and the same automatic record player. The known adaptor comprises a first ring provided with an internal annular recess adaped to receive a gramophone record, and a second ring which is attached to the first ring partly before and partly after insertion of the gramophone record.
U.S. Pat. No. 2,646,284 (herewith incorporated by reference) describes an intricate adaptor for gramophone records, which comprises a metal disc formed with a small centre hole, a first plastic ring with a large opening adapted to receive a gramophone record, a soft ring interposed between the metal disc and the plastic ring, and a second plastic ring intended to retain the gramophone record in the large opening.
It is further known to use a central adaptor to enable gramophone records of different types to be played on the same record player. Some currently commercially available gramophone records, namely the long-play records, have a small center hole for co-operation with a thin rotatable spindle of the record player and other records, referred to as the singles, are provided with a large center hole. By mounting a disc-shaped adaptor having a small center hole in the large center hole of the last-mentioned records these records are adapted to co-operate with the thin rotatable spindle of the record player.
Until recently only one type of optical disc carrying audio information was available, namely the Compact Disc (CD), so that such problems did not occur in the field of optical discs. However, recently a smaller version of the Compact Disc has been put on the market, which version has a smaller outer diameter than the CD. The new type of Compact Disc, also referred to as "CD single" or "mini CD", has an outer diameter of 80 mm. The original Compact Disc has an outer diameter of 120 mm. A problem arising by the introduction of the CD single is that the smaller optical disc cannot readily co-operate with all optical apparatuses intended for the original Compact Disc. For example, the disc-loading mechanism of existing optical audio equipment is not constructed to accept such small discs. Moreover, the small optical discs cannot readily be accommodated in the known storage cases and trays.
On account of their nature and construction the adaptors known from the cited U.S. Patents are not suitable for use in conjunction with the small vulnerable CD-singles.